This is more of a basic understanding of the GMAT's problem solving questions. I've noticed a pattern of GMAT problem solving questions which are solved using this type of formula:

X+Y=Z
uX+vY=wZ
(insert any random number into "uvw". It could read as 2X+3Y=4Z)

What is the best approach to solving this types of problems? I tend to have difficulty figuring out which variable to plug in or substitute in order to solve the problem quickly.

Thanks for your help!

To solve one that has three variables, generally speaking, we need to have three equations (that are different from each other.)
Our goal is to combine two of the equations and eliminate a single variable, or, if you get really lucky, two variables.

There's not really a prescribed way to proceed - and there's really not a wrong way to proceed on these either. Your goal is to isolate and substitute - and eliminate as much as possible in each step.

If you'll post a specific question on this, I can help you solve it, though - or walk you through the process and the reasoning behind the different steps..

Veritas Help